Abstract:The present study has employed in vitro autoradiography to study the distribution and density of [3H]zolpidem binding sites, which are regarded as an index of ethanol-sensitive gamma-aminobutyric acid (GABA)A receptors, in the brains of alcohol-preferring Fawn-Hooded (FH) rats compared to non-alcohol preferring Wistar-Kyoto (WKY) rats. Binding of [3H]zolpidem showed a similar distribution profile in both rat strains examined and included cerebellum, globus pallidus, nucleus of the solitary tract and a number of midbrain/hindbrain nuclei. Densitometric quantitation of binding revealed that FH rats possessed a significantly higher density of [3H]zolpidem binding compared to WKY rats in cortical regions, substantia nigra pars reticulata and the ventral pallidum. These data indicate that FH rats may have an increased number of ethanol-sensitive GABA(A) receptors in regions intimately involved in reward processes, and may partially explain the alcohol-seeking nature of the FH rat.